Laser rangefinder sighting apparatus and method

ABSTRACT

A sighting assembly comprising a housing having a first portion and a second portion has mounted within the first portion thereof a laser rangefinder comprising a laser transceiver for transmitting a laser beam toward a target and for receiving a reflected laser beam from the target. The laser rangefinder is coupled to a display for indicating the distance to the target. Mounted within the second portion of the housing is a sight for viewing the target. The sighting assembly further includes at least one attachment on the housing for securing the assembly to a weapon.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 60/781,084 filed Mar. 9, 2006; that application is incorporated herein, by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to optical systems and particularly to laser rangefinder sighting apparatus and methods.

2. Description of the Related Art

A laser rangefinder is an optical transceiver capable of determining the distance between the rangefinder and the target. A rangefinder includes a laser light source or laser transmitter and a photo detector or laser light receiver. Typically, the laser transmitter irradiates the target with one or more incident laser light pulses and the laser receiver receives the light pulses reflected from the target. A processor in the rangefinder determines the difference between the time of the transmission of a pulse and the time of the reception of the reflected pulse back at the rangefinder receiver. Using this time difference, the processor computes the range of the target. A numerical representation of the range may be displayed on a suitable electronic display on the rangefinder.

A laser rangefinder may have a first optical channel for transmitting the laser light pulses, a second optical channel for receiving the reflected pulse, and a third optical channel for viewing or visualizing the target. Each of these channels may have its own separate optical axis. Alternatively, portions of the optical axes of the receiving and viewing channels may be arranged along a common parallel axis, all three channels may be arranged coaxially, or still further, in parallel and coaxial combinations.

Multifunction, integrated systems combining laser rangefinders, telescopic and/or direct view optics, infrared optics, CCD-based visible TV subsystems, and so forth, have also been developed. These systems are generally designed for military use and therefore tend to be complex, bulky and expensive. For example, U.S. Pat. No. 6,020,994 discloses a multifunction, multispectral military sight assembly having numerous reflective, refractive and other optical components that must be carefully aligned. Thus, there remains a need for an integrated sight assembly that is simple and compact (that is, one that does not require complex and/or bulky optical systems), and that is moreover light weight and inexpensive. Such an assembly would have particular utility for rifles, pistols and bows used in recreational sport and hunting activities.

SUMMARY OF THE INVENTION

In accordance with one specific, exemplary embodiment of the invention, there is provided a sighting assembly comprising a housing having a first portion and a second portion. Mounted within the first portion of the housing is a laser rangefinder comprising a laser transceiver for transmitting a laser beam toward a target and for receiving a reflected laser beam from the target. The laser rangefinder is coupled to a display for indicating the distance to the target. Mounted within the second portion of the housing is a sight for viewing the target. The sighting assembly further includes at least one attachment on the housing for securing the assembly to a weapon.

Preferably the sight comprises a scope that may include a reticle. In one form of the invention, the reticle comprises elevation graduations.

In another form of the invention, the laser transceiver transmits and receives substantially along a first optical axis and the sight views the target along a second optical axis. The first and second optical axes may be fixed relative to each other. Alternatively, the first and second optical axes may comprise separate, parallel axes. As another alternative, the first and second optical axes may be substantially coaxial.

In yet another form of the invention, the sight may comprise a scope enclosing a reflecting surface positioned to intercept the first and second optical axes, the reflecting surface being adapted to redirect the laser beam transmitted by the laser transceiver to travel along the first optical axis and to redirect the laser beam reflected from the target to travel toward the transceiver.

The reflecting surface may comprise a mirror fixed relative to the housing and preferably the mirror may be smaller than the total optical diameter of the scope.

In still a further form of the invention, the sight may comprise a scope enclosing a beam splitter positioned to intercept the first and second optical axes, the beam splitter being adapted to (1) redirect the laser beam transmitted by the laser transceiver to travel along the first optical axis; (2) redirect the laser beam reflected from the target to travel toward the transceiver; and (3) transmit a view of the target along the second optical axis to an eyepiece of the scope.

According to another aspect of the invention, the laser rangefinder display may be mounted on the upper portion of the housing. Alternatively, the display may be mounted within an eyepiece of the scope.

Still further, the sighting assembly may also comprise a processor responsive to an output of the laser rangefinder for providing to the display information representative of the distance to the target.

The sighting assembly may comprise a processor connected to an output of the laser rangefinder for providing a control signal responsive to the output, the control signal being coupled to adjust an optical sighting element carried by the scope to automatically correct for projectile deflections.

Pursuant to another specific, exemplary embodiment of the invention, there is provided a weapon system comprising a weapon, a scope attached to the weapon for viewing a target, a trajectory compensating system for providing a distance indicative of the drop of a projectile fired by the weapon, and an adjustment system coupled to the scope for adjusting the alignment of the scope relative to the weapon in response to the distance signals. The adjustment system may adjust the elevation angle of the scope in response to the distance signal. The weapon system may further include a display for displaying the distance between the weapon and the target in response to the distance signal.

In accordance with yet another specific, exemplary embodiment of the invention, there is provided a method comprising providing a weapon comprising a projectile bore having an axis, the weapon having mounted thereon (1) a sighting assembly comprising a laser rangefinder coupled to a range display and having an optical axis, and (2) a scope having a graduated reticle and an optical axis, the optical axes and the bore axis being parallel; sighting through the scope to acquire an image of the target; reading the display to determine the range to the target; and adjusting the orientation of the weapon to compensate for projectile deflection based on the range. The projectile deflection may comprise projectile drop and the adjusting of the weapon orientation comprises adjusting the elevation of the weapon. Still further, prior to adjusting the orientation of the weapon, an optical element of the scope may be adjusted in response to the determination of range.

Preferably, the adjusting of the optical element is performed automatically.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features, aspects and advantages of the present invention will become better understood with reference to the accompanying example drawings in which:

FIG. 1 is a side elevation view of a portion of a weapon system in accordance with the first exemplary embodiment of the invention;

FIG. 2 is a side elevation view, partly in cross section, of a laser rangefinder sighting assembly forming part of the weapon system depicted in FIG. 1;

FIG. 3 is an end elevation view, in cross section, of the weapon system of FIG. 1 as seen along the line 3-3 in FIG. 1, illustrating schematically the views seen by the shooter;

FIG. 4 is a side elevation view, partly in cross section, of a portion of a weapon system in accordance with an alternative embodiment of the invention;

FIG. 5 is an end elevation view in cross section of the weapon system of FIG. 4 as seen along the line 5-5 in FIG. 4;

FIG. 6 is a side elevation view, partly in cross section of a sighting assembly for use in a weapon system in accordance with an alternative embodiment of the invention;

FIG. 7 is a side elevation view, partly in cross section, of a sighting assembly for use in a weapon system in accordance with another alternative embodiment of the invention;

FIG. 8 is a side elevation view, partly in cross section, of a sighting assembly for use in a weapon system in accordance with a further alternative embodiment of the invention; and

FIG. 9 is a side elevation view, partly in cross section, of a portion of a sighting assembly for use in a weapon system in accordance with yet another alternative embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Generally, in accordance with one aspect of the present invention, there is provided apparatus and methods of mechanically packaging or integrating a laser rangefinder directly into a sighting assembly that can accurately determine the range to a target and provide sighting or aiming capabilities at low cost.

The various embodiments of the invention all utilize various optical and electronic components that are well known in the art and accordingly these components are not described or shown in detail.

FIG. 1 is a side elevation view of a weapons system 10 in accordance with one specific, exemplary embodiment of the present invention. Generally, the system 10 comprises a ranging and sighting assembly 12 mounted on a weapon such as a rifle 14 by means of at least one attachment and preferably by means of fore and aft rail-type attachments 16 and 18. Instead of a rifle, the weapon may comprise a pistol, bow or other sport or hunting weapon. Generally, the ranging and sighting assembly 12 combines a laser rangefinder and a sight such as a scope enclosed within a single, unitary housing 20 attached to the rifle.

Turning now also to FIG. 2, the housing 20 comprises an interchangeable upper portion 22 and lower portion 24. The upper portion 22 contains a laser rangefinder 26 comprising an optical transceiver 28 including a transmitter that emits a laser beam 30 along an optical axis 32 and a laser detector that receives a beam 34 reflected from the target along the axis 32. The transceiver 28 provides to a processor 36 a signal indicating the range of the target. The processor 36, in a manner well known in the art, computes the range and provides an output signal to a display 38 representing the distance. The display 38, mounted, for example, at the rear of the upper portion 22 of the housing 20, provides a visual representation of the distance in the form, for example, of a digital readout 40 (FIG. 3) that may be observed by the shooter along the optical axis of the laser rangefinder. Such displays and the visual images produced thereby in response to the output of a laser rangefinder are well known in the art. The display 38 may, for example, comprise a liquid crystal display, a light emitting diode display, a CRT display, or the like. The processor 36 may be programmed by entering appropriate instructions into the memory of the processor through a port 42 and associated bus 44 compatible with a standard such as the USB standard. The instructions may include the ballistics of the projectile that is to be fired. The port 42 may also receive a battery charger if rechargeable batteries are used to power the system.

The processor 36 may include logic circuitry to calculate the deflection from windage and projectile drop based on the type of projectile to be used. Such information is typically provided in tables that the user can consult. However, the processor can do this if provided with the ballistic information, then use this data to determine how far the image should be deflected for a given target distance.

The transceiver 28 is secured to the upper portion 22 of the housing so that it at all times is in a fixed position relative thereto. Both the transmitted and reflected beams 30 and 34 travel substantially along the same optical axis 32.

The lower portion 24 of the housing 20 incorporates a sight which may comprise an optical sighting scope 46 comprising, as well known in the art, an eyepiece 48 through which the shooter views the target, rotatable rings 50 and 52 for adjusting such optical properties as magnification and focus, a reticle 54 and an objective lens 56 at the far end of the scope. The eyepiece, reticle and objective lens are aligned along an optical axis 58 extending parallel with the optical axis 32 of the laser rangefinder.

FIG. 3 illustrates in schematic form the views seen by the shooter. The shooter first acquires the target by sighting through the scope eyepiece 48, then moves his line of sight to the digital range readout or display 38 and, having acquired that information moves his eye back to the eyepiece 48, adjusts the elevation of the rifle as required in accordance with a vertical scale 60 on the reticle 54 and then fires the weapon. The system will typically include a push button or other switch for triggering the laser rangefinder.

As noted, in the embodiment of FIGS. 1-3, the scope and laser rangefinder form an assembly integrated into a single housing. It will be understood, however, that in general, the advantages of the invention may be realized so long as the scope and laser rangefinder are closely coupled.

It will be seen that the embodiment of FIGS. 1-3 provides a manual system that is extremely simple. The transmitted and reflected laser beams 30 and 34 lie substantially along the same optical axis 32 thereby eliminating the necessity of carefully aligning separate transmitter and receiver optical axes. Further, none of the parts is movable, eliminating errors produced by relatively movable components.

FIGS. 4 and 5 show in schematic form a ranging and sighting assembly 100 for attachment to a weapon 102 in accordance with a second embodiment of the invention. The ranging and sighting assembly 100 of the second embodiment comprises a single, unitary housing 104 having an upper portion 106 enclosing a laser rangefinder 108 and a lower portion 110 incorporating a sight that may comprise a scope 112. The laser rangefinder 108 comprises, as before, a transceiver 114 for transmitting an incident laser beam 116 along an optical axis 118 and for receiving a reflected laser beam 120 along the same optical axis 118. The transceiver 114 is boresighted to the optical axis of the sighting assembly. The transceiver generates a range signal applied as an input to a processor 122 also contained within the upper portion 106 of the housing. The processor 122, in turn, generates an output signal applied to a display 124 within an eyepiece 126 of the scope. By integrating the display within the eyepiece, movement of the shooter's line of sight as required in the first embodiment is eliminated. Such movement is undesirable because it may be detected by the target or reacquisition of the target may be difficult if the target moves. With the second embodiment, the shooter can compensate for projectile drop and/or lateral deflection with virtually no delay.

With reference to FIG. 6, there is shown in schematic form a ranging and sighting assembly 130 for inclusion in a weapon system in accordance with a third embodiment of the invention. As before, the ranging and sighting assembly 130 of the third embodiment comprises a single, unitary housing 132 having an upper portion 134 enclosing a laser rangefinder 136 and a lower portion 138 containing a sight which may be in the form of a scope 140. The laser rangefinder 136 comprises a laser beam transceiver 142 for transmitting a laser beam 144 toward a target and for receiving a reflected beam 146 from the target. The transceiver 142 is secured to an inner surface of the housing 132 so as to be fixed relative thereto.

Besides the lenses and reticle previously described, the scope 140 encloses an optical element in the form of a beam splitter 148. The beam splitter 148 is disposed to receive from the laser transceiver 142 the transmitted laser beam 144 that is reflected by the beam splitter 148 and thereby projected toward a target along an optical axis 150 that may coincide or essentially coincide with, or be closely parallel to, the optical axis of the scope 140. The laser beam 146 reflected from the target enters the front of the scope along the optical axis 150, and is reflected by the beam splitter and directed from there to the transceiver 142. A view of the target is seen along the optical axis 150 through the beam splitter 148. The beam splitter 148 is selected to reflect laser wavelengths and to transmit visible light wavelengths to an eyepiece 152. The coaxiality or coincidence of the optical axes of the rangefinder and the scope enhances the thermal and mechanical stability of the sighting assembly.

The beam splitter 148 is preferably coated so that the light beams to and from the transceiver 142 are reflected and the light from the target is transmitted to the eyepiece 152. The laser transceiver 142 may transmit and be responsive to light at various wavelengths, such as the visible and/or infrared regions of the electromagnetic spectrum.

The laser transceiver 142 provides an output to a processor 154 in turn having an output coupled to a display 156 mounted in the rear of the upper portion 134 of the housing or within the scope's eyepiece 152, as previously described. It will be evident that the embodiment of FIG. 6 may be modified to provide for an internal display 158 within the eyepiece 152, as in a fourth embodiment depicted in FIG. 7. The processor 154 provides an output signal representing the range to the display along a bus 160.

With reference to FIG. 8, there is shown in schematic form a ranging and sighting assembly 200 for inclusion in a weapon system in accordance with a fifth embodiment of the invention. As before, the ranging and sighting assembly 200 of the fifth embodiment comprises a single, unitary housing 202 having an upper portion 204 enclosing a laser rangefinder 206 and a lower portion 208 containing a sight that may be in the form of a scope 210. The laser rangefinder 206 comprises a laser beam transceiver 212 for transmitting a laser beam 214 toward a target and for receiving a reflected beam 216 from the target. The transceiver 212 is preferably secured to an inner surface of the housing 202 so as to be fixed thereto.

Besides the lenses and reticle previously described, the scope 210 preferably encloses an optical element in the form of a small, fixed position mirror 218. The mirror 218 is preferably smaller than the total optical diameter of the scope and is so angularly oriented to reflect all or nearly all of the laser energy. The mirror 218 is disposed to receive from the laser transceiver 212 the transmitted laser beam 214 which is reflected by the mirror and thereby projected toward a target along an optical axis that may coincide or essentially coincide with or be closely parallel to the optical axis 220 of the scope 210. The laser beam 216 reflected from the target enters the front of the scope along the optical axis and is reflected by the small mirror 218 and directed from there to the transceiver 212. A view of the target bypasses the small mirror and is seen directly in an eyepiece 222 along the optical axis 220.

Further alternatives will suggest themselves to those skilled in the art. The most complete integrated embodiment of the invention would have “closed loop” control of the sighting of the weapon by determining the range to the target, computing the correction required for the given range, applying the correction to the sighting device, and providing an indication in the display of the readiness of the weapon. For example, pursuant to another embodiment of the invention, FIG. 9 depicts a portion of a laser rangefinder and scope assembly 170 that is fully automated. The assembly 170 comprises a laser rangefinder (not shown), a processor 172 coupled to an output 174 of the rangefinder, and a scope 176 having an eyepiece 178 and a reticle 180. In the embodiment of FIG. 9, the reticle 180 is adjustably mounted so that its position may be controlled by an actuator (not shown). The assembly 170 includes a feedback path 182 between the processor 172 and the reticle 180 (or other optical element) for automatically adjusting the position thereof in response to the range computed by the processor 172. Preferably, the position of an optical graduated hairline image incident on the reticle is controlled by the processor.

It will be further evident that laser rangefinders producing laser emissions of various wavelengths may be used. Those wavelengths may comprise, by way of example and not limitation, 0.8-0.98 microns, 1.53-1.58 microns 1.062-1.066 microns and 1.180-1.200 microns.

The integrated, internal or external, parallel or coaxial optical approach may provide for automatic ballistic compensation based on range, initial or muzzle velocity, and/or ballistic coefficient of the projectile. The display may include ranging distance. For example, as already explained, the system may provide for automatically holding, lowering or raising the reticle to compensate for projectile rise and drop. The user would designate the target using the laser rangefinder and the reticle would be automatically moved to compensate for projectile flight. Also, by displaying the range, the user may determine the feasibility or probability of hitting the target.

The system is intended for embedding, external use and/or integrated with telescopic, that is, optics-based scopes, direct view optical sighting systems, camera based sighting systems in which a view of the target may be displayed via a CCD sensor or detector array, conventional “iron sights”, pin sights, fiber optic based sights, low light sights, infrared sights (both 3-5 micron and 8-12 micron infrared sighting systems and/or subsets of those wavelengths), illuminated sights, laser dot and/or designater based sights, aiming apparatus or offhand/unaided sighting approaches, that can be used on small and large bore rifles, pistols, and bows for the purpose of simultaneous or sequential range finding and aiming and/or aiming compensation of projectile trajectories used in recreational hunting, sport, and like applications. The laser rangefinder and optical scope may be mounted coaxially or in a parallel manner or in a combined coaxial and parallel fashion. The system may also be used with an infrared sighting system or with a combined infrared and visible light sighting system.

It will be evident from the foregoing that various embodiments of the invention may include a totally external laser rangefinder integration (i.e., external laser transmitter, external detector and electronics); an external laser transmitter and internal laser detector receiver and the electronics either internal or external; an internal laser transmitter and internal laser detector receiver with the electronics either internal or external; and an internal laser transmitter and external laser detector receiver with the electronics either internal or external.

The embodiments of the invention described herein are exemplary and numerous modifications, variations and rearrangements can be readily envisioned to achieve substantially equivalent results, all of which are intended to be embraced within the spirit and scope of the invention as defined in the appended claims. 

1. A sighting assembly comprising: a housing having a first portion and a second portion; a laser rangefinder mounted within the first portion of the housing, the laser rangefinder comprising a laser transceiver for transmitting a laser beam toward a target and for receiving a reflected laser beam from said target, the laser rangefinder being coupled to a display for indicating the distance to the target; a sight mounted in the second portion of the housing for viewing the target; and at least one attachment on said housing for securing the assembly to a weapon.
 2. The assembly of claim 1 in which: the sight comprises a scope.
 3. The assembly of claim 2 in which: the scope includes a reticle.
 4. The assembly of claim 3 in which: the reticle comprises elevation graduations.
 5. The assembly of claim 1 in which: the laser transceiver transmits and receives substantially along a first optical axis and the sight views the target along a second optical axis.
 6. The assembly of claim 5 in which: the first and second optical axes are fixed relative to each other.
 7. The assembly of claim 5 in which: the first and second optical axes are separate, parallel axes.
 8. The assembly of claim 5 in which: the first and second optical axes are substantially coaxial.
 9. The assembly of claim 1 in which: the sight comprises a scope enclosing a reflecting surface positioned to intercept the first and second optical axes, the reflecting surface being adapted to (1) redirect the laser beam transmitted by the laser transceiver to travel along the first optical axis; and (2) redirect the laser beam reflected from the target to travel toward the transceiver.
 10. The assembly of claim 9 in which: the reflecting surface comprises a mirror fixed relative to the housing.
 11. The assembly of claim 9 in which: the mirror is smaller than the total optical diameter of the scope.
 12. The assembly of claim 1 in which: the sight comprises a scope enclosing a beam splitter positioned to intercept the first and second optical axes, the beam splitter being adapted to (1) redirect the laser beam transmitted by the laser transceiver to travel along the first optical axis; (2) redirect the laser beam reflected from the target to travel toward the transceiver; and (3) transmit a view of the target along the second optical axis to an eyepiece of the scope.
 13. The assembly of claim 1 in which: the display is mounted on the upper portion of the housing.
 14. The assembly of claim 1 in which: the display is mounted within an eyepiece of the scope.
 15. The assembly of claim 1 further comprising: a processor responsive to an output of the laser rangefinder for providing to said display information representative of the distance to the target.
 16. The assembly of claim 1 further comprising: a processor connected to an output of the laser rangefinder for providing a control signal responsive to said output, said control signal being coupled to adjust an optical sighting element carried by the scope to automatically correct for projectile deflections.
 17. A weapon system, comprising: a weapon; a scope attached to said weapon for viewing a target; a trajectory compensating system which provides a distance which indicates the projectile drop of a projectile fired by said weapon; and an adjustment system coupled to said scope for adjusting the alignment of said scope relative to said weapon in response to said distance signals.
 18. The system of claim 17, in which: said adjustment system adjusts the elevation angle of said scope in response to said distance signal.
 19. The system of claim 17, further including: a display for displaying the distance between said weapon and said target in response to said distance signal.
 20. A method of sighting a target comprising: providing a weapon comprising a projectile bore having an axis, the weapon having mounted thereon (1) a sighting assembly comprising a laser rangefinder coupled to a range display and having an optical axis, and (2) a scope having a graduated reticle and an optical axis, said optical axes and said bore axis being parallel; sighting through said scope to acquire an image of said target; reading the display to determine the range to said target; and adjusting the orientation of the weapon to compensate for projectile deflection based on the range.
 21. The method of claim 20 in which: the projectile deflection comprises projectile drop and the adjusting of the weapon orientation comprises adjusting the elevation of the weapon.
 22. The method of claim 20 further comprising: prior to adjusting the orientation of the weapon, adjusting an optical element of the scope in response to the determination of range.
 23. The method of claim 22 wherein: the adjusting of the optical element is performed automatically. 